Probably not, but bad grounds on E Ignitions are known to cause misses at higher rpms. Just a thought. Injuneer most likely right on this one though.JMHO

 

I would go with the 42#ers, you will need a tune either way, so might as well get a little more headroom

 

Many people try to "tune" by changing the fuel pressure. In a closed loop system, that doesn't work. The PCM "corrects" the pulse widths to compensate for the fuel pressure change.

But there is nothing wrong with running a higher fuel pressure, to reduce duty cycle. I run 58psi, so my Bosch 64's act like they are 78's. The LS1's run at 58psi. Nothing wrong, except the stock Rochester Products ball and seat injectors do not like fuel pressure above 60psi or so.

Best thing to do it to simply upgrade to a larger injector, stick with the stock fuel pressure, and program the PCM accordingly.

I just find it hard to believe no one suggested that your stock injectors might be too small for the flywheel HP you are running.

The online injector calculators don't relate to a specific A/F ratio. They are based on Brake Specific Fuel Consumption (BSFC) at max fuel demand. BSFC is expressed in #/HR/HP. Most online calculators assume a BSFC of 0.50 #/HR/HP for the calculation. That is a representative value for a factory tune. Not necessarily a "good" tune for max power/torque.

Actual BSFC has to be measured on an engine dyno. An efficient tune for a drag car might be in the 0.45 #/HR/HP. My engine dyno tests show an 0.44 #/HR/HP BSFC at max fuel demand. That's a decent tune. I suspect engines that are run closer to a constant RPM, like a NASCAR engine may approach 0.40 BSFC.

The use of a very conservative BSFC like 0.50, and an 80% DC will produce a result that says a stock 24# injector (24.9 flow constant) is only good for about 320 flywheelHP. That's why the factory picked the injector size they did, and why they went up to a 28# injector on the LT4 (good for 360HP using the conservative approach). They don't want to push the injector past 80% DC.

For most well tuned applications, you can drop below 0.50, and push the injector into the 85-90% DC area, but I wouldn't want to run them any higher than that.

 

Yeah I can't believe that nowhere along the way not a single person ever mentioned injectors to me... Even when I got it rebuilt I asked the shop to put in everything I would need and they never mentioned it so I figured I was okay... Well either way, looks like I might just finally fix my miss!!!